The Absorbent Mind. Maria Montessori MontessoriЧитать онлайн книгу.
not only provoked meditation but has also roused the attention of many scientists who have made these cells the object of their studies. By observation with a powerful microscope, it has been found that each cell contains a certain number of points which as they can be very easily colored by chemical means have been called ‘Chromosomes’ Their number differs in the different species. In the human species for instance, there are 48. In others there are 15, in some 13 so that the number of chromosomes distinguishes the species to which they belong. Scientists thought that these chromosomes had something to do with the formation of the organs. Recently much more powerful microscopes have been invented. These allow one to see things which it was absolutely impossible to see previously. They have been called ultra -microscopes, and by their means people have been able to see that each of the chromosomes was a sort of a little box which contained a sort of chain, composed of about 100 little grains. The chromosomes break up, the grains free themselves and the cell becomes the depositary of some four thousand little grains that have been termed ‘genes’ (Fig. 2.) The word genes implies the idea of generation. They have been so called because the characteristics of the body are formed by their combinations.
This is really science. Yet if one stops to think what this implies, one realizes how mystic this dry scientific statement sounds, for this cell is so tiny as to be almost invisible, yet it contains within itself the heredity of all times. In this little speck, there is the whole experience, the whole history of the human kind. Before any apparent change is visible in the primitive cell, already a combination among these genes has taken place. They have already arranged themselves to determine exactly the form of the nose, the color of the eyes etc. of the being that will result from this primitive cell. Not all the genes are employed in the formation of a body. A sort of struggle takes place between these genes; only a few combine and these give the outer characters of the individual while others remain hidden and obscure. For instance, there is the famous example of Mendel who made an experiment. He crossed a plant with red flowers and one of the same kind with white flowers and then the seeds of the new plant were sown. These produce either three plants with white and one with red flowers or the contrary. So out of 40 seeds, 30 will come with red flowers and 1 with white flowers or 1 with red and 30 with white. If the circumstances are good, it is the superior qualities that prevail; but if the circumstances are not favorable, then it is the worse qualities that come forth. So according to the circumstances in which the cell finds itself, you can have a more beautiful individual or a less beautiful individual, a stronger individual or a weaker individual. And this is due to the combinations between the genes. The combinations are so many that every human being is different from every other and even if one observes families that have many children, though all the children are generated by the same parents, yet some are beautiful, others ugly; some are tall, others short and so forth.
Today much time is spent in studying what are the circumstances which will make the better characters come forth; a new science has arisen, Eugenics, which shows how man has by his intelligence succeeded in acquiring influence even over heredity. Human intelligence has understood that heredity can be influenced only at the stage when the primitive cell is formed and changes can be made. Thus man becomes a sort of god who takes in hand the powers of life and orients the path it will take. Nothing much has been done in this direction in the field of humanity, but in that of plants and animals, man has been able to influence heredity to a great extent. What does it mean when one has the power of life in one’s hand? It means that we can dispose of heredity so as to transform the species. This is the fascinating part that in our days focuses on this science the interest of hundreds upon hundreds of people. Today this interest is not academic or philosophical. Today it has invaded the practical field. Great numbers of plants and animals have been transformed. Some years ago, for instance, two young men carried out certain biological experiments and a race of stingless bees was produced which made a great deal more honey. So man has been able to influence the life of these insects and to create a species that has become harmless and produces more of a nourishing substance that humanity appreciates. In the same way certain plants have been transformed so as to produce much more food than they did previously. Men have also transformed simple roses into the many beautiful varieties that today gladden our eyes and delight our sense of smell. In the case of flowers great achievements have been made. Man has captured a secret of life. He has become a sort of magician who has embellished life with the magic wand of his intelligence; because of it, the world is much richer and more pleasant. We begin to see one of the aims of the life of man, one of the reasons which makes him one of the great cosmic forces. He has not been placed in the world in order to enjoy beautiful things. He has been placed here to make the world better. Man has intelligence because he has to make a better world than that which he has found. It is as though man were the continuation of the creation, as though he had been sent to employ his intelligence in order to help and make creation more perfect. Intelligence is the great gift that has been given to him. Man has been able to enter a field that permits him to have control over life. Hitherto man had to follow life as it was, but now he can control it. So the study of embryology is no longer an abstract and fruitless study. It is a study which has allowed man to penetrate certain secrets of life and to be able to control by means of these secrets the beings that are to come. Now, if by a stretch of imagination we think that psychic development follows a similar procedure, then we can imagine that man, who has penetrated the secrets of physical development, can also control and help psychic development.
This chapter about genes and heredity is separate from pure embryology. Embryology considers only the way in which the primitive cell produces the individual. To do this, the ultra -microscope or special reasoning are not required. It is merely a question of observation. From one cell, two are generated and these remain joined. Then the two become four, the four eight, eight become sixteen and so on. This continues until hundreds of cells are produced which are similar to the bricks that are used for the construction of a house. Eventually a sort of hollow sphere is produced. Curiously enough, in the oceans, there are certain animals which are just like that, a hollow ball, and they are called ‘volvo’ because they are always going round. Then these balls become inflected and form two walls and later a third wall is formed between the two. So the first construction consists of these three walls. Up to now all cells are alike amongst themselves. Only they are smaller than the primitive cell. (Fig. 3.)
Recently studies have permitted the discovery of the way in which these organs are formed. I mentioned this fact in the previous chapter. This discovery Was made very recently, between 1929 and 1930 i.e., after the first world war. Now this is 14 years ago. Before a discovery is made and this discovery is made public and every one knows about it, 14 years are, we might say, as yesterday. Now the figure reproduced here does not correspond to a reality. (Fig. 4.)
It is something imaginary made in order to show points of sensitivity. There are these spots in which cells begin to multiply very fast and it is in these special points that organs are formed. While one person discovered this in America, in England independently somebody else was also doing research work and he made the same discovery. The American called these points ‘gradients,’ the Englishman, as he made his discovery upon the nervous system, called them ‘points of sensitization’ and ‘sanglion.’
Each of the three walls of the gastrula produces a set of organs. The external one produces the skin, the sensory organs and nervous system. And this illustrates that the external layer is in relation with the environment, because the skin gives us protection and the nervous system places us in relation to the environment. The innermost one develops organs used for nourishment such as the intestines, stomach, the glands of digestion, liver, pancreas, and the lungs. The organs of the nervous systems are called organs of relation because they allow us to put ourselves in relation with the environment. The organs